Aortic Aneurysm

IF YOU ARE HAVING SEVERE CHEST, BACK, OR BELLY PAIN, OR IF YOU THINK YOU ARE HAVING A HEART ATTACK OR STROKE, IMMEDIATELY GO TO A HOSPITAL EMERGENCY DEPARTMENT. DO NOT ATTEMPT TO DRIVE YOURSELF. CALL 911 FOR EMERGENCY MEDICAL TRANSPORT.

Abnormal enlargement or bulging of the aorta, the largest blood vessel of the body, is not an unusual condition. Medical professionals refer to this as aneurysm of the great vessel, or aortic aneurysm. The enlargement usually affects only a small part of the vessel, so bulge is a more accurate description.

An aneurysm occurs when a segment of the vessel becomes weakened. The pressure of the blood flowing through the vessel creates a bulge at the weak spot, much as an overinflated inner tube can cause a bulge in a tire. The bulge usually starts small and grows as the pressure continues. Aneurysms are dangerous because they can rupture, causing internal bleeding.

The aorta is an artery, meaning it carries oxygen-rich blood from the heart. It is the main artery coming from the heart.

• It extends from the left chamber (ventricle) of the heart and goes through the chest, down through the belly, or midsection of the body (abdomen), and into the pelvis (groin).
  
  
• In the groin, it divides into 2 vessels that supply blood to the lower trunk and both legs.
  
  
• In the chest, the aorta is called the thoracic aorta; in the abdomen, the abdominal aorta.

Almost every artery in the body branches off of the aorta. These arteries supply blood to the brain, other vital organs (liver, stomach, small and large bowel, spinal cord) and nerves, bones, muscles, and cells that allow the body to function.

• Damage to the aorta can threaten vital functions.
  
  
• If the damage is severe enough, or not treated, it can even cause death.

Bulging can occur in any artery in the body. It is most common in the arteries of the brain and in the abdominal aorta.

• In the aorta, bulging can occur anywhere along the entire vessel.
  
  
• It is most common in the abdominal aorta, where it is known as abdominal aortic aneurysm ("triple AAA").
  
  
• If it occurs in the thoracic aorta, it is known as thoracic aortic aneurysm.

Arteries are muscular tubes. The wall of the artery is made up of 3 layers: the innermost layer (the intima), the middle layer (the media), and the outer layer (the adventitia). Bulges in an artery are classified as "true" aneurysm, "false" aneurysm, or dissection.

• A true aneurysm involves all 3 layers of the blood vessel wall.
  
  
• A false aneurysm of the artery is contained only by the 2 outer layers of the blood vessel wall and clot. This is a very fragile condition with high risk of bursting. False aneurysms are usually a result of an infection.

A related but different condition is aortic dissection. Dissection refers to a separation of the vessel wall, which allows blood to leak between the layers of the vessel. This further damages and weakens the vessel, placing it at much greater risk of bursting (rupture).

Because the abdominal aorta is such a large vessel, a ruptured abdominal aneurysm is a life-threatening event.

• Fortunately, not all aneurysms rupture right away. Many grow very slowly and cause no symptoms or problems for many years.
  
  

• When detected in time, most aneurysms can be electively repaired with an operation so they do not rupture.

Each year, about 15,000 people in the United States die of a ruptured abdominal aneurysm. This makes it the 13th leading cause of death in this country.

• Most aneurysms occur in people aged 55 years or older.
  
  
• The number of aneurysms in the United States is increasing as the population increases and ages.
  
  
• Aneurysms are 4 times more common in men than in women.

An aortic aneurysm develops from a weakness in the wall of the aorta. This weakness can be present since birth or can develop as the result of disease or injury.

• Atherosclerosis: A clogged or damaged artery from a condition called atherosclerosis is the most common cause of aneurysm. Atherosclerosis is often called "hardening of the arteries" because it calcifies later in life. In atherosclerosis, a fatty substance (cholesterol) called plaque sticks to the lining of the blood vessel wall, weakening the wall. Atherosclerosis is also the most common cause of heart disease and heart attack.
  
  
• High blood pressure: When you have high blood pressure, it puts stress on the wall of the aorta. Over many years, this stress can lead to bulging of the blood vessel wall. This is the leading factor in development of aneurysms of the thoracic aorta.
  
  
• Diabetes: Uncontrolled diabetes damages blood vessels by premature, accelerated atherosclerosis, leaving them vulnerable to a number of conditions including aneurysm formation.
  
  
• Cystic medial necrosis: In this condition, the medial layer of the blood vessel wall degenerates, and an abnormal fibrous layer weakens the supporting structure of the blood vessel wall itself. This commonly occurs with certain rare inherited conditions such as Marfan syndrome and Ehlers-Danlos syndrome. It also occurs with heart valve disease and pregnancy.
  
  
• Mycotic aneurysm occurs when bacteria spread into the arterial system, invade the blood vessel wall, and weaken the vessel. Often the bacteria enter areas of previous damage or areas weakened since birth. Although rare today, the advanced form of the sexually transmitted disease syphilis was a common cause of this condition in the early part of the 20th century.
  
  
• Inflammatory aneurysm: Inflammatory conditions or vasculitis, such as psoriasis and rheumatoid arthritis, may produce inflammation in the blood vessel wall itself. If the inflammation is not reversed, it eventually weakens the wall of the aorta. Vasculitis generally affects the smaller to medium sized vessels and rarely the aorta.
  
  
• Injury: Injury to the chest or abdomen, as in a car wreck or bad fall, can damage an area of the aorta. This leaves the aorta vulnerable to bulging.

In many cases, the cause of an aortic aneurysm is never known.

Risk factors for aortic aneurysm include the following:

• Age 55 years or older
  
  
• Male sex
  
  
• High blood pressure
  
  
• Smoking
  
  
• Inherited diseases that cause weakening of the blood vessels, with emphasis on Marfan syndrome 
  
  
• Family history of aortic aneurysm

Aneurysms usually do not cause any symptoms until they become very large or rupture. Aneurysms in the abdominal aorta are often found coincidentally when the individual undergoes a medical test or procedure for some other reason.

Chest pain and back pain are the 2 most common symptoms of large aneurysms.

• Almost any unusual sensation or feeling in the upper chest or back, however, may be due to an aneurysm of the aorta.
  
  
• Chest pain is usually the first sign of aortic dissection. Many people describe a tearing or ripping pain in the chest when the aorta enlarges to a critical size and ruptures/dissects. Besides pain, increased sweating, a fast heart rate, rapid breathing, dizziness, and shock may occur.

Some people describe the following symptoms of an aortic aneurysm:

• A pulsating bulge or a strong pulse in the abdomen
  
  
• Feeling of fullness after minimal food intake
  
  
• Nausea
  
  
• Vomiting

Where the aorta widens into a bulge, blood clots (thrombi) are more likely to form. If a piece of a blood clot breaks off, it travels through the circulatory system until it lodges somewhere. The clot can cut off blood flow to any area of the body. Symptoms depend on which part of the body is deprived of blood.

• In the most serious cases, the broken off fragments can cause stroke or heart attack. The fragments can also cause one or more vital body organs, such as the lungs, liver, or kidneys, to stop functioning properly. 
  
  
• In less serious cases, it might cause numbness, weakness, tingling, pallor, or coldness in an arm or leg, loss of sensation, light-headedness, or localized pain.

Any of these symptoms can also occur with dissection of the aorta. The pain in the chest or pain may be particularly severe, and may mimic a heart attack.

In ruptured aneurysm or dissection, internal bleeding will occur. If you have any of these symptoms along with the other symptoms of aortic aneurysm, you could be in danger and must seek emergency medical care right away. Other symptoms include the following:

• Light-headedness
  
  
• Confusion
  
  
• Weakness
  
  
• Shortness of breath
  
  
• Rapid heart beat
  
  
• Sweating
  
  
• Numbness or tingling
  
  
• Loss of consciousness (fainting)

This is a medical emergency. If the bleeding is uncontrolled, your blood pressure will drop dangerously low. Your organs will not receive enough blood to function normally. This is called circulatory collapse, or just "shock."

• This is a life-threatening condition.
  
  
• You lose consciousness if your brain does not receive enough blood.
  
  
• Your other organs may start to fail.
  
  
• Your heart can stop beating. This is called cardiac arrest and is often fatal.

Any time you experience chest pain or the sensation that something is "just not right" in your chest, consult a medical professional.

If you notice a strong pulse sensation, or a pulsating bulge in your abdomen, you should see your health care provider right away.

If the pain is new, "tearing" or "ripping" in quality, severe, or frightening, go immediately to a hospital emergency department. Do not "wait it out," because immediate treatment can be life saving for aneurysm/dissection as well as in other conditions that cause chest pain.

If an aortic aneurysm ruptures, you will have internal bleeding. This is a medical emergency, because a person can bleed to death in a few minutes.

Severe back, flank, or abdominal pain may be the only symptom of an enlarging aorta. Many other conditions can cause these symptoms, but an aortic aneurysm is the most serious of these conditions.

Most aortic aneurysms cause no symptoms and are found when you undergo a medical test or procedure for some other reason. Others are found only when you have symptoms.

The typical symptoms of an abdominal aortic aneurysm are not specific. This means that they could be caused by a number of different conditions.

• Your health care provider will probably not know at first what is causing your symptoms. He or she will rapidly consider the possibilities and develop a plan for systematically ruling each one out.
  
  
• This evaluation will start with the most serious conditions, and ruptured aneurysm is near the top of the list.
  
  
• If you are able, you can help by giving a focused, detailed description of how the symptoms started, how you were feeling before they started, and how the situation progressed once the symptoms started.

A full exam, with special attention to the cardiovascular system and abdomen, will give clues to the diagnosis.

• The health care provider may be able to feel a pulsating bulge in your belly or hear a loud pulse or other signs of aortic enlargement with the stethoscope.
  
  
• The exam findings will guide the rest of the evaluation.

Probably the first test that will be performed is an electrocardiogram (ECG or EKG). This is done to rule out a heart attack and other serious heart conditions.

• A series of electrical wires will be attached to your chest, arms, and legs. The ECG records the electrical impulses that control the beating of your heart.
  
  
• The rate and rhythm of your heartbeat is measured.
  
  
• Abnormalities in the ECG may point to heart damage.
  
  
• Often the ECG result is normal in uncomplicated aortic aneurysm.
  
  
• The test may be repeated after a short time to see if any changes have occurred in heart function.

An ultrasound, x-ray, computed tomography (CT) scan, angiogram, or magnetic resonance imaging (MRI) of the chest and abdomen may be done.

• Usually, an aneurysm shows up on plain radiographs only if it has become calcified as a result of atherosclerosis.
  
  
• Ultrasound will show abnormalities in the shape of your aorta. Echocardiography is a special type of ultrasound that shows the heart in great detail. This may be done in certain situations in which heart damage is suspected and/or the thoracic aorta is thought to be involved. A transesophageal echocardiogram is more sensitive and specific; the procedure involves swallowing a long tube with a probe at its distal end. Prior to placement of the probe, local anesthesia is applied to the back of the throat. This probe is very sensitive and can easily identify heart or aortic problems within a few minutes.
  
  

• Aortography is an x-ray procedure done after a contrast or x-ray dye is injected into the blood stream. This study highlights abnormalities, such as bulges, and confirms the diagnosis of aneurysm. Aortography involves inserting a catheter inside the body and aorta, with its associated risks.

• A CT scan is a fancy x-ray that shows much more detail of the organs, blood vessels, and other structures inside the body. It requires the use of a dye, which can damage the kidney in rare cases.
  
  
• MRI is also a fancy, highly specialized technique that gives a very detailed view of the inside of the body.
  
  
• CT scan and MRI have largely replaced aortography. The only hazard of CT scan and MRI is that the patient is left unattended in a radiological suite for about 20-30 minutes, which may not be advisable for a patient with low blood pressure.

|Self-Care at Home|

Do not try to treat yourself at home or "wait it out." Severe chest, abdominal, or back pain, especially with symptoms that suggest internal bleeding, requires immediate, expert medical attention and rapid diagnosis.  

In an estimated 20% of cases, the first sign or symptom of an unrecognized abdominal aortic aneurysm is rupture that leads to sudden death from massive blood loss.

|Medical Treatment|

The treatment of this condition depends on your overall health, the size and location of the aneurysm, and whether you are having symptoms. The risks and benefits of surgery for abdominal aortic aneurysms are different than those for thoracic aortic aneurysms.

Abdominal aortic aneurysms are unlikely to rupture if they develop slowly, are less than 5.5 cm (about 2 inches) in diameter, and are causing no symptoms.

• In these cases, the risk of rupture over the next 5 years is considered negligible. The risks involved with surgery outweigh the risk of the aneurysm rupturing.
  
  
• Close monitoring of the aneurysm size is the proper treatment for most people.
  
  
• Ultrasound/CT scan every 6-12 months is the usual monitoring strategy. This may vary by individual patient and health care provider.
  
  
• As the aneurysm enlarges to greater than 5.5 cm, surgical correction is the treatment of choice.

Any abdominal aortic aneurysm larger than about 2 inches (5.5 cm) in size requires surgery to repair it. Aneurysms that are enlarging rapidly, causing symptoms, or showing signs of probably rupture (such as leaking) require immediate surgery. Delaying this surgery puts you at even greater risk of a rupture.

• The risk of rupture of an abdominal aortic aneurysm greater than 2.7 inches (7 cm) in diameter is almost 20%.

Thoracic aortic aneurysms may originate in either the ascending or descending aorta and, because of their closer proximity to the heart than abdominal aortic aneurysms, they have greater potential to harm the heart or create other problems related to the heart.

• The need for more aggressive treatment is balanced by the higher risk of surgery closer to the heart.
  
  
• Generally, about 2.3 inches (6 cm) is the critical size for atherosclerotic aneurysms.
  
  
• Any thoracic aortic aneurysm 6 cm or larger requires surgery, but if you have Marfan syndrome or a familial history of aneurysms, 5-cm aneurysms are considered for surgery. 
  
  
• Aneurysms at the aortic root (nearer the heart) are prone to rupture at sizes closer to 5 cm and must be treated more aggressively.

In most cases, a medication (beta-blocker) that lowers blood pressure and relieves stress on the artery wall will be given to reduce the stress on the weakened part of the vessel. Lowering of blood pressure is usually done in the intensive care unit with intravenous medications and continuous monitoring of the blood pressure.

|Surgery|

Although a ruptured aortic aneurysm can be repaired by surgery, these cases tend to be less successful than in those individuals who undergo surgery for unruptured aneurysms. Generally only about 50% of people who undergo urgent surgery for repair of a ruptured aneurysm survive. Even in those who survive surgery, kidney failure, dead bowel, and leg ischemia are common complications.

Open surgery has long been the accepted treatment for aortic aneurysms of the chest or abdomen.

• A large incision is made in the chest or the abdomen.
  
  
• Blood flow in the aorta is stopped by hooking the circulatory system to an outside pump (heart and lung machine). This machine circulates blood to the body and keeps the vital organs and other tissues oxygenated properly. 
  
  
• The damaged section of the aorta is removed and replaced by an artificial blood vessel (graft) made of cloth fabric. The graft is sewn in place.
  
  
• Although this surgery is usually successful, it has its own risks to the heart, brain, lungs, and kidneys. It also involves considerable recovery time because of the size of the incision and complexity of the surgery. Usually a patient has to stay in the hospital for a week, and recovery time is at least 6 weeks. 

Abdominal aortic aneurysm

Treatment for these aneurysms has recently focused on procedures that are less invasive than conventional surgery.

• One widely used alternative is stenting of the aneurysm by a vascular surgeon or an interventional radiologist.
  
  
• A "stent" is a tiny metal and fabric device like a miniature scaffold. It is threaded through the blood vessel from a small incision, usually in the groin. A thin plastic tube called a catheter is used to thread the stent through the blood vessel.
  
  
• The stent is fastened to the inner vessel wall just above the level of weakened aortic wall to help support the blood vessel. This reduces strain on an existing aneurysm and can prevent a full-blown aneurysm from developing again. 
  
  
• Stenting is not only much faster than conventional surgery, it offers much shorter recovery time and fewer complications. However, long-term outcomes are not known and only a few centers in North America do such procedures. The appropriate choice of procedure, open versus stenting, depends on many factors and is best determined by your primary care provider and vascular surgery team.

Thoracic aortic aneurysm

• Surgical repair of these aneurysms requires full cardiopulmonary bypass by a thoracic surgeon.
  
  
• Stenting of thoracic aortic aneurysms has been shown to be possible, but clinical experience is much less than in abdominal aneurysms, and considered more experimental.

|Prevention|

No medicine can prevent an aortic aneurysm. However, measures can be taken that will help keep your blood vessels healthy and strong.  

• Eat a low-fat, low-cholesterol diet.
  
  
• Get active: Take part every day in some activity that increases your heart rate to the rate recommended for your age and overall condition. At least 30 minutes a day is ideal.
  
  
• Don't smoke.
  
  
• Control your blood pressure.

If you are found to have an aortic aneurysm less than 5 cm in size, it should be watched carefully by your primary care provider. Regular ultrasound examinations will detect any growth or other changes in the aneurysm.

Some experts recommend screening for all individuals older than 55 years.

• Screening would detect many aortic aneurysms that otherwise go unrecognized because they cause no symptoms.
  
  
• Ultrasound examination of the abdomen is more than 80% accurate in screening for the existence of abdominal aortic aneurysm. Physical exam may not detect an aneurysm.

|Outlook|

With prompt diagnosis and proper surgical treatment, most people recover fully.

Treatment usually requires minimal alteration of lifestyle, although recommendations to avoid dietary fat and smoking and to control blood pressure may allow you to prevent further damage to your blood vessels.

Because these conditions most often occur in elderly people with other medical conditions, recovery can be prolonged and difficult.

Complications of untreated aortic aneurysm include the following:

• Blood clot: Where the aorta widens into a bulge, blood clots (thrombi) are more likely to form. If a piece of a blood clot breaks off (embolizes), it travels through the circulatory system until it lodges somewhere. The clot can cut off blood flow to any area of the body. Symptoms depend on which part of the body is deprived of blood.
  
  
• Internal bleeding: In ruptured aneurysm or dissection, internal bleeding will occur. If you have symptoms associated with internal bleeding, you are in danger and must seek emergency medical care right away.
  
  
• Circulatory shock: If you bleed enough, your blood pressure will drop dangerously low. Your organs will not receive enough blood to function normally. This is called circulatory collapse or often just "shock." It is a life-threatening condition.

|Support Groups and Counseling|

American Heart Association
National Center
7272 Greenville Avenue
Dallas, TX 75231
(800) 242-8721

|Web Links|

American Heart Association

abdominal aneurysm, aortic aneurysm, aortic bulge, aortic dissection, atherosclerosis, bulging of the aorta, high blood pressure, hypertension, leaking aneurysm, aortic rupture, triple AAA, ascending and descending aortic aneurysms, heart lung machine, cardiopulmonary bypass

Author: Shabir Bhimji, MD, Consulting Surgeon, Cardiac Surgical Associates of West Texas.

Coauthor(s): Bryan Hoynak, MD, Assistant Professor, Department of Emergency Medicine, University of California at Irvine; Kathryn L Hale, MS, PA-C, Medical Writer, .com, Inc.

Editors: Alan D Forker, MD, Program Director of Cardiovascular Fellowship, Professor of Medicine, Department of Internal Medicine, University of Missouri at Kansas City School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, ; Anthony Anker, MD, FAAEM, Attending Physician, Emergency Department, Mary Washington Hospital, Fredericksburg, VA.